Energy levels of light nuclei A=8,9,10

Energy levels of A = 21−44 nuclei (V)

https://www.cns.s.u-tokyo.ac.jp/~shimoura/research/nuc_data/pdf/11.pdf

Energy levels of light nuclei A = 11-12

This article provides an overview of the basic principles of the physics of quantum halo systems, defined as bound states of clusters of particles with a radius extending well into classically forbidden regions. Exploiting the consequences of this definition, the authors derive the conditions for occurrence in terms of the number of clusters, binding energy, angular momentum, cluster charges, and excitation energy. All these quantities must be small. The article discusses the transitions between different cluster divisions and the importance of thresholds for cluster or particle decay, with particular attention to the Efimov effect and the related exotic states. The pertinent properties can be described by the use of dimensionless variables. Then universal and specific properties can be distinguished, as shown in a series of examples selected from nuclear, atomic, and molecular systems. The neutron dripline is especially interesting for nuclei and negative ions for atoms. For molecules, in which the cluster division comes naturally, a wider range of possibilities exists. Halos in two dimensions have very different properties, and their states are easily spatially extended, whereas Borromean systems are unlikely and spatially confined. The Efimov effect and the Thomas collapse occur only for dimensions between 2.3 and 3.8 and thus not for 2. High-energy reactions directly probe the halo structure. The authors discuss the reaction mechanisms for high-energy nuclear few-body halo breakup on light, intermediate, and heavy nuclear targets. For light targets, the strong interaction dominates, while for heavy targets, the Coulomb interaction dominates. For intermediate targets these processes are of comparable magnitude. As in atomic and molecular physics, a geometric impact-parameter picture is very appropriate. Finally, the authors briefly consider the complementary processes involving electroweak probes available through beta decay, electromagnetic transitions, and capture reactions.

Structure and reactions of quantum halos

The experimental and theoretical evidence for intrinsic reflection-asymmetric shapes in nuclei is reviewed. The theoretical methods discussed cover a wide spectrum, from mean-field theory and its extensions to algebraic and cluster approaches. The experimental data for nuclear ground states and at low and high spin, cited as evidence for reflection asymmetry, are collected and categorized. The extensive data on electric dipole transition moments and their theoretical interpretation are surveyed, along with available data on electric octupole moments. The evidence for reflection-asymmetric molecular states in light nuclei is summarized. The application of reflection-asymmetric theories to descriptions of the fission barrier, bimodal fission, superdeformation, and hyperdeformations is reviewed, and some other perspectives in the wider context of nuclear physics are also given. [S0034-6861(96)00102-X]

Intrinsic reflection asymmetry in atomic nuclei

The Doppler shift attenuation method has been used to make two measurements of the mean life of the $^{11}\mathrm{Be}$ 320-keV level. The results are 150\ifmmode\pm\else\textpm\fi{}30 fs from the $^{9}\mathrm{Be}(t, \mathrm{p}\ensuremath{\gamma})^{11}\mathrm{Be}$ reaction and 168\ifmmode\pm\else\textpm\fi{}17 fs from the $^{3}\mathrm{H}(^{9}\mathrm{Be}, \mathrm{p}\ensuremath{\gamma})^{11}\mathrm{Be}$ reaction. The adopted value of 166\ifmmode\pm\else\textpm\fi{}15 fs, from the present and previous measurements, corresponds to an extremely strong $E1$ transition of 0.36\ifmmode\pm\else\textpm\fi{}0.03 W.u. The adopted energy of the ground state transition from this and previous measurements is 320.04\ifmmode\pm\else\textpm\fi{}0.10 keV. It is shown that the magnitude of this $E1$ transition can be understood on the basis of shell-model calculations only if realistic single-particle wave functions are used. A similar theoretical treatment is given for strong $E1$ transitions in $^{9}\mathrm{Be}$ and $^{13}\mathrm{C}$.NUCLEAR REACTIONS $^{9}\mathrm{Be}(t, \mathrm{p}\ensuremath{\gamma})^{11}\mathrm{Be}$, $E(\mathrm{t})=1.5\ensuremath{-}3.3$ MeV, $^{3}\mathrm{H}(^{9}\mathrm{Be}, \mathrm{p}\ensuremath{\gamma})^{11}\mathrm{Be}$, $E(^{9}\mathrm{Be})=10\ensuremath{-}16$ MeV; measured DSA; deduced $\ensuremath{\tau}(^{11}\mathrm{Be}, 320\ensuremath{-}\mathrm{k}\mathrm{e}\mathrm{V})$; calculated $B(E1)$, $B(M2)$ from thoery and compared to experiment for $^{9}\mathrm{Be}$, $^{11}\mathrm{Be}$, $^{13}\mathrm{C}$.

Strong E-1 transitions in Be-9, Be-11, and C-13

Measurement of the Quadrupole Moment ofLi8by Use of a Polarized Deuteron Beam and NMR Detection

For more than ten years, we have been working on R&D for X-band accelerator structures for the JLC/NLC linear collider. Several types of Detuned (DS) and Damped Detuned Structures (DDS) have been successfully designed and fabricated. They have been experimentally tested at both low power and high power to characterize their mechanical and electrical properties. Recently we started developing a new type of damped detuned structure with optimized round-shaped cavities (RDDS). This paper discusses the special specifications, design methods, fabrication procedures, measurement technologies, and anticipated future improvements for all these structures.

Accelerator structure R&D for linear colliders

The Mossbauer effect of57Fe implanted into diamond structure semiconductors, Ge, Si and C, has been studied by in-beam implantation of57Fe ions, which were excited to the 14 keV state by a35Cl beam from a tandem Van de Graaff accelerator. The time between the stopping of the57Fe nucleus and the emission of the 14 keV γ-ray is determined by the lifetime (140 ns) of the 14 keV state. In each material the Mossbauer spectrum exhibits a doublet with velocity coordinates (in mm/s) at room temperature, relative to a sodium ferrocyanide absorber, as follows: diamond (−0.99, 1.10), silicon (−0.80, 0.21), and germanium (−0.88, −0.02). In silicon and germanium crystals the spectra were observed over the temperature range between 13 K and 870 K. The relative line intensities changed dramatically and the positions of the lines shifted systematically with temperature. In addition, channelling studies were made on iron that had been implanted into silicon.

In-beam implantation of iron into germanium, silicon and diamond studied by the Mössbauer effect

We have measured total cross sections for the reaction [pi][sup +][ital p][r arrow][pi][sup +][pi][sup [minus]][ital p] at incident pion kinetic energies of 190, 200, 220, 240, and 260 MeV We use this result to deduce a new value of the chiral symmetry breaking parameter, [xi]=[minus]025[plus minus]010, in a global constrained fit of the five [pi][pi][ital N] near-threshold amplitudes Consequently, we report new soft pion model values for the [ital s]-wave [pi][pi] scattering lengths

S. S. Hanna

Papers

Strong E-1 transitions in Be-9, Be-11, and C-13

Measurement of the Quadrupole Moment ofLi8by Use of a Polarized Deuteron Beam and NMR Detection

Accelerator structure R&D for linear colliders

In-beam implantation of iron into germanium, silicon and diamond studied by the Mössbauer effect

Reaction pi +p--> pi + pi 0p near threshold and chiral symmetry breaking.